/**
 * Created by goto9 on 2019/3/8.
 */
class PubSub {
  constructor() {
    this.PubSubCache = {
      $uid: 0
    };
  }

  on(type, handler) {
	  console.log('collection',handler)
    let cache = this.PubSubCache[type] || (this.PubSubCache[type] = {});
	console.log('cache',cache);
    handler.$uid = handler.$uid || this.PubSubCache.$uid++;
	console.log('handler',handler.$uid);
    cache[handler.$uid] = handler;
  }

  emit(type, ...param) {
    let cache = this.PubSubCache[type],
      key,
      tmp;

    if(!cache) return;

    for(key in cache) {
      tmp = cache[key];
      cache[key].call(this, ...param);
    }
  }

  off(type, handler) {
    let counter = 0,
      $type,
      cache = this.PubSubCache[type];

    if(handler == null) {
      if(!cache) return true;
      return !!this.PubSubCache[type] && (delete this.PubSubCache[type]);
    } else {
      !!this.PubSubCache[type] && (delete this.PubSubCache[type][handler.$uid]);
    }

    for($type in cache) {
      counter++;
    }

    return !counter && (delete this.PubSubCache[type]);
  }
}
export default new PubSub()